tuliskan 4 bilangan pertama dari barisan un=2n²-n-2

Un = 2n^2 - n -1
U1 = 2(1)^2 - 1 - 1 = 2-1-1 = 0
U2 = 2(2)^2 - 2 -1 = 8-2-1= 5
U3 = 2(3)^2 -3 -1 = 18 -3 -1 = 14
U4 = 2(4)^2 -4 -1 = 32 -4 -1 = 27
0, 5, 14, 27.